Thirty-two years ago, on March 1, 1954, U.S. scientists exploded the first deliverable hydrogen bomb on the tiny coral atoll of Bikini in the Marshall Islands. To their surprise, the explosion was more than twice the yield expected.

At 15 megatons (the equivalent of 15 million tons of TNT), the blast obliterated the island and heaved tons of radioactive fallout across the Pacific to the east rather than to the north as U.S. scientists had expected.

Within four hours, white radioactive particles began falling like snow on the 64 Marshallese men, women and children who lived on Rongelap, an atoll 105 miles east from Bikini. Four hours later the fallout began to drop on Rongerik, another Pacific island where 28 U.S. weathermen were stationed.

The "rain" of radioactive white powder continued for 12 hours. It came down on the roofs of the Marshallese houses and, with an evening rainfall, was washed into barrels that were the prime source of drinking water. It covered the fish and coconuts drying in the sun for that evening's meal.

This U.S. nuclear accident, the victims of which are still experiencing medical effects, carries dramatic echoes and lessons for the Soviet Union today as Moscow attempts to deal with the long-term effects of the Chernobyl reactor incident. The Soviets have been widely criticized for failing to publicly announce the disaster until it was detected in western Europe and for underplaying the health hazards involved.

Following the 1954 Bikini blast, the U.S. government initially was silent, waiting 10 days before acknowledging to the world that the Marshallese and American servicemen had been exposed to radioactive fallout.

That disclosure came only after a small U.S. newspaper received a letter from a U.S. Marine on Kwajalein reporting that natives and servicemen had arrived at that base "suffering from various burns and radioactivity."

U.S. officials initially maintained that the Marshallese had not been exposed to dangerous radiation levels, that they had been taken to Kwajalein "according to plans as a precautionary measure" and that no effects had appeared. In fact, some victims were suffering from classic symptoms of radiation exposure: burns, nausea and hair loss.

Seven years earlier, when the first atomic tests were conducted on Bikini and the weapons were in the relatively modest 15-kiloton range (the equivalent of 15,000 tons of TNT), Rongelap was considered in a threatened zone and the islanders were moved from their homes in boats.

For the 1954 blast, they were notified of the test but told that there was less danger and no need to take precautions.

The U.S. servicemen on Rongerik had a similar experience. However, they had been given fallout recording devices by Atomic Energy Commission (AEC) scientists, who told the troops that the devices were designed to record only low levels of radiation. If the readings went "off scale" and indicated greater contamination, the servicemen were to immediately notify their headquarters on the atoll of Enewetak.

Little more than one hour after a white mist began to fall on Rongerik, about eight hours after detonation, the devices went "off scale." At 3 p.m., calls went to the Enewetak headquarters which initially suggested that something was wrong with the devices. That night, after dust falling on tents began to glow, the troops were told to stay indoors and plans were made to evacuate them to a Navy hospital on Kwajalein.

For the Marshallese on Rongelap, it was not until March 3, more than 40 hours after the first radiocative fallout began, that a U.S. Navy destroyer arrived to evacuate them from the island.

As the contamination became public and it became an issue in the Cold War with the Soviet Union, the United States continued to put the most optimistic assessment on the event.

On March 16, more than two weeks after the blast, the Japanese announced that one of their fishing boats, the Lucky Dragon, had been caught in the radioactive fallout. Two days later, a U.S. official in Japan said the exposed fishermen, some of whom showed symptoms of radiation burns and sickness, would recover completely in about a month. Not long after, one died.

The question of public disclosure was eventually overshadowed by other serious issues -- again, perhaps foreshadowing Chernobyl -- including the question of how the released radiation would affect the health of the exposed individuals and the land.

The average Rongelap inhabitant received roughly a 175-rad dose, according to a 1982 U.S. government report. Under current standards, a worker in a nuclear plant can receive about five rads a year without ill health effects.

Four weeks after the explosion, the white blood counts of the Rongelapese dropped to 30 percent of what is considered normal.

On April 1, 1954, AEC Commissioner Lewis Strauss appeared at a news conference with then-President Dwight D. Eisenhower. He made the first public disclosure of the power of an H-bomb and, buried within the question-and-answer period, he declared that he had met with the Marshallese and that no serious illness had been uncovered.

For three years, the Rongelap people remained away from their island because it was considered too radioactive. When they returned in 1957, their diet was limited to imported food. Last year, 31 years after the blast, the northern islands of the Rongelap Atoll were found to still contain unsafe levels of radiation in coconuts and other crops; consequently, the Rongelap people finally abandoned their homes and moved to another atoll.

In the interim, all 15 children who were under the age of 10 at the time of the radiation exposure suffered thyroid abnormalities. One child, a year old at the time of the explosion, died of leukemia; miscarriages and stillbirths among the exposed women were more than twice the normal rate and deaths were 30 percent higher.